US 12,408,337 B2
Three-dimensional memory device including composite backside metal fill structures and methods for forming the same
Fumitaka Amano, Yokkaichi (JP); and Ryo Kambayashi, Yokkaichi (JP)
Assigned to Sandisk Technologies, Inc., Milpitas, CA (US)
Filed by SANDISK TECHNOLOGIES LLC, Addison, TX (US)
Filed on Jun. 10, 2022, as Appl. No. 17/806,406.
Prior Publication US 2023/0403850 A1, Dec. 14, 2023
Int. Cl. H10B 41/35 (2023.01); H01L 23/48 (2006.01); H10B 41/10 (2023.01); H10B 41/27 (2023.01); H10B 43/10 (2023.01); H10B 43/27 (2023.01); H10B 43/35 (2023.01)
CPC H10B 41/35 (2023.02) [H01L 23/481 (2013.01); H10B 41/10 (2023.02); H10B 41/27 (2023.02); H10B 43/10 (2023.02); H10B 43/27 (2023.02); H10B 43/35 (2023.02)] 5 Claims
OG exemplary drawing
 
2. A three dimensional memory device, comprising:
an alternating stack of insulating layers and electrically conductive layers;
memory openings vertically extending through the alternating stack;
memory opening fill structures located in the memory openings and comprising a respective vertical semiconductor channel and a respective vertical stack of memory elements; and
a backside trench fill structure laterally extending along a first horizontal direction,
wherein:
the backside trench fill structure comprises a backside trench insulating spacer and a backside contact via structure that is laterally surrounded by the backside trench insulating spacer; and
the backside contact via structure comprises:
a first metal layer;
a second metallic nitride liner comprising a nitride of the first metal and contacting an inner sidewall of the first metal layer;
a tapered metallic nitride liner is located inside the second metallic nitride liner; and
at least one core fill conductive material portion that is laterally surrounded by the second metallic nitride liner;
the first metal layer comprises tungsten and the second metallic nitride liner comprises tungsten nitride;
the tapered metallic nitride liner comprises tungsten nitride;
the at least one core fill conductive material portion comprises a tungsten fill material portion having an opposite stress state than the second metallic nitride liner; and
the backside contact via structure further comprises a second metal layer located between the second metallic nitride liner and the at least one core fill conductive material portion.